As composite materials simultaneously having properties of organic polymer and inorganic compound, there have been conventionally, industrially and widely used mixtures of: a general-purpose polymer such as polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(methyl methacrylate) (PMMA), nylon (PA), or polyester (PET); and an inorganic compound such as talc (calcium carbonate), clay, and silica. However, as materials exhibiting characteristics better than the conventional composite materials, there have been variously developed hybrid materials comprising organic-inorganic polymer hybrids, which have organic polymer moieties and inorganic oxide moieties combining each other and constituting composite structures (see Patent document 1).
As organic polymers in such organic-inorganic polymer hybrids, there have been utilized various polymers other than the conventional general-purpose polymers. For example, polyimides, which exhibit excellent gas permeability for gas separation application (see Patent document 2-4), have extremely excellent heat resistance, mechanical strength, electric characteristic, chemical resistance, and processing characteristic in addition to gas permeability, so that there have been developed various hybrid materials comprising organic-inorganic polymer hybrids based on polyimides (see Non-patent document 1). Polyimides in the conventional organic-inorganic polymer hybrids have been typically straight-chain (linear) polyimides which are respectively obtained by reacting: aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride and biphenyl tetracarboxylic dianhydride; and aromatic diamines such as diamino diphenyl ether.
Although the conventional hybrid materials comprising polyimide-based organic-inorganic polymer hybrids exhibit various excellent characteristics derived from composite structures including polyimide moieties and inorganic oxide moieties which combine each other, there are recently demanded novel hybrid materials exhibiting better characteristics, thereby leaving room for further investigation and improvement.
Patent document 1: JP-A-2004-277512
Patent document 2: JP-A-57-15819
Patent document 3: JP-A-60-82103
Patent document 4: JP-A-60-257805
Non-Patent document 1: Yamada, Yasuharu, and two others, “Property of silicon-containing polyimide, and application thereof”, Extra issue of monthly “Polymer Processing”, published by koubunshikankoukai, February 1997, vol. 46, No. 2, pp. 2-11